<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>triangle</title>
</head>
<body>


<script>
    for(var j=0;j<5;j++)
    {
        for(var i=0;i<=j;i++)
        {
            document.write("*");
        }
        document.write("<br/>");
    }
</script>
</body>
</html>